Questions are now being raised over why the widening of the A465 has taken so long and led to the value of the two projects being compared.

And green campaigners have argued that the cost of the A465 widening outweighs the benefits, citing an Oxford University professor’s report criticising major infrastructure project calculations as “garbage”.

Supporters argue that the widening of the road is vital to the economic future of the Valleys and will improve road safety, help regeneration and link residents to education, health centres and jobs.

Brian Morgan, professor of entrepreneurship at Cardiff Metropolitan University, said it was a “a really sad situation” that the project had taken so long and led to it being carried out while major improvements were needed to the M4.

He said: “We shouldn’t be in this position because the dualling of the Heads of the Valleys should have been completed by 2012. It’s been delayed and delayed and delayed and what’s so terrible is it’s a shovel-ready project.”

Prof Morgan said every Welsh government since 1999 had “failed to invest infrastructure despite the largesse of the first 10 years in government when we had that massive increase in the block grant.”

He said he regretted that people were now looking at the “opportunity cost of one road over the other,” saying: “We need both and we need them now and we need to find ways in which the infrastructure budget can be expanded.”

Former Swansea University economist John Ball went further, suggesting that investing in public transport within the Heads of the Valleys would be a better form of investment.

He said: “I think we have got to think very seriously about forms of public transport. It’s a relatively poor area; we should be talking about rail links and bus links.”

However, he acknowledged the importance of a trade route to the Midlands from the Valleys.

Environmentalists contrasted the road’s costs with the Welsh Government’s cuts to bus grants and failure to expand Ebbw Vale’s popular rail service.

The Welsh Government confirmed last week it will cut funding for bus services in 2013-14 to £25m from £33m in 2011-12.

Green campaigners cited a report by Oxford University professor Bent Flyvbjerg, an international expert on major projects, who claimed infrastructure forecasts were inaccurate.

“Many forecasts are garbage and can be shown to be worse than garbage. These reports give the client, investors and others the impression that they are being informed about future demand, or the costs involved in a major project, when they are being misinformed,” he wrote.

Matt Hemsley, of Sustrans Cymru, said: “This [Oxford] report highlights significant issues with transport forecasting, so the benefits are likely to be even lower than currently thought.

“We know that 30% of households in that part of Wales don’t have access to a car.”

He said concentrating so much of the transport budget on road schemes forced deprived families to own cars, placing “great burden” on household budgets.

Gareth Clubb, director of Friends of the Earth Cymru, said: “It’s as if the government don’t see that the way people travel and think about travel has changed in the last 20 years.

“Road traffic has dropped by some 5% since 2007, instead of growing by 5%, so there’s a gap of about 10% between what the transport planners would have expected by now and the actual traffic.

“It’s a lot to spend on one road.” especially when money is short and travelling habits are changing. Young people these days want to spend their time online.”

The Welsh Government had scaled down infrastructure for the 2008 Ebbw Vale rail reopening to save money, but the trains to Cardiff carried more passengers than forecast. “Now there’s not enough capacity for them to run more trains,” he said.

Poor safety on parts of the A465 should be tackled through measures such as average-speed cameras and lower speed limits at blackspots, added Mr Clubb.

The Welsh Government said dualling would help relieve the M4 by diverting some long-distance traffic.

“As well as the direct transport benefits such as improved journey times and safety, the A465 dualling will provide a catalyst for regional development of the Heads of the Valleys area to support employment and to stimulate economic growth,” said a spokesman.

“The dualling will improve access to and from labour markets and other vital public services such as health, leisure and education, improving the attractiveness of areas as places to live and work.”

The case for dualling the remaining sections was based on Department for Transport data from April 2011, which reflected lack of traffic growth in recent years but predicted further growth when the economy improved.

Next page: Supporters argue widening the A465 is vital

Supporters of the widening of the A465 said it would make the area more attractive to business.

Victoria Winckler, director of the Bevan Foundation think tank, said it was the region’s only route between towns and to the Midlands and West Wales.

“Funding for bus services and encouraging people to cycle and walk is about local journeys. I wouldn’t want to cycle from Merthyr to Abergavenny with a suitcase and two kids,” she said.

The dualling schemes would benefit bus passengers if they resulted in improvements to the area’s “pitiful” buses, which took an hour and a half from Merthyr to Abergavenny, she said.

Traditional forecasts for infrastructure schemes may under-value people’s lives, she added. “It would be hard to tell the families of anyone who has been killed or seriously injured on the road that it’s not worth it [the cost of dualling]. It’s a fast road, in places it’s three lanes, and it’s got short exits.”

Huw Lewis, AM for Merthyr Tydfil and Rhymney, said: “I have long campaigned for dualling the Heads of the Valleys road here in Merthyr Tydfil, as this is vital to widen access, support businesses and improve the safety of the current layout.

“The dualling of the road is inextricably linked to the economic future of the Valleys and, as the local AM, I am delighted that the Welsh Labour government has confirmed its commitment to this project.”

The most recent analysis from the Department for Transport suggests the dualling scheme will provide £1.52 of benefits for every £1 spent.

This figure reflects the expected “wider economic benefits” of upgrading the road between Brynmawr and Tredegar.

Major transport funding has traditionally been targeted at projects offering “high” value for money – at least £2 of benefits per £1 spent.

Without those wider economic benefits, the scheme is expected to deliver £1.30 of benefits for every £1 invested.

The Department for Transport rates schemes as offering “low” value for money if the benefits are below £1.50 for every £1 invested.

Next page: The costs

Total cost of dualling

The figures below show the cost, or expected cost, of dualling each section of the Heads of the Valleys road. The costs include design, construction, land acquisition, compensation, VAT and allowance for risk. All figures are at current prices.

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